U.S. Pat. No. 3,178,463 discloses the formation of compounds of iron, ruthenium and osmium in which three carbonyl groups and a compound containing a cyclopentadiene configuration are bonded to the metal atom. Said compounds are depicted by the empirical formula C.sub.y HM(CO).sub.3, wherein C.sub.y H is a cyclopentadiene hydrocarbon and M is an iron subgroup metal, i.e., iron, ruthenium or osmium.
U.S. Pat. No. 4,674,447 discloses improvements in the operation of gasoline internal combustion engines in which the gasoline contains an organic manganese compounds.
U.S. Pat. No. 4,946,975 discloses a process for making methylcyclopentadienyl manganese tricarbonyl compounds. The process disclosed involves forming a mixture of bis(methylcyclopentadienyl) manganese and manganese acetate, reacting this mixture with an alkyl aluminum compound in the presence of an ether donor compound in an amount to provide about 1 mole of ether per mole of aluminum alkyl and reacting the resultant product with carbon monoxide to produce methylcyclopentadienyl manganese tricarbonyl.